<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <div id="app">
    体重kg: <input type="number" v-model="weight">
    身高m: <input type="number" v-model="height">
    {{bmi}}
  </div>
  <script src="./vue.global.js"></script>
  <script>
    const { createApp } = Vue;
    const app = createApp({
      data(){
        return {
          weight: 0,
          height: 0
        }
      },
      computed: {
        bmi(){
          return this.weight / (this.height*this.height)
        }
      }
    })
    app.mount('#app')
  </script>
</body>
</html>